"Of course defence of property is murder"
Not according to English law. A person "may use such force as is reasonable in the circumstances in the prevention of crime or in arresting offenders or suspects". Obviously deciding to shoot someone because they are taking your property would be murder, but if you go in with the intention to use reasonable force to prevent it, and the person either ignores you and continues to steal, or resists, then they have escalated it and if you found yourself in a position where you could either kill them to stop them theiving, or allow them to take your property, you could kill them and have a defence in law for doing so.
"What is so precious about your car that it's worth killing someone to keep it on your driveway? Do people not have insurance that would replace it?"
Of course it's insured but that isn't the point, why would you want to live life as a perpetual victim, having to "allow" people to take what they like just because you can claim it back. That costs the insurance companies, who will then hike up my premiums, and it lets a thief go free to potentially do more damage. My property belongs to me, the thief has no right to try and take it whereas I have every right to try and stop it being taken. If a thief is confronted and then makes the decision to escalate by resisting or whatever, then it's their fault if the home owner is forced to kill them to protect property. Fortunately there is an easy way to nullify this threat to the safety of burglars, they can elect not to try and steal stuff that isn't theirs.